The re-positioning plan will be specific to your strategy and property, particularly the pace that you want to realize the value for future deals and your debt structure.Regarding the test scenario, if it works, the $50-75/mo incremental increase will certainly justify the rehab cost you mentioned at most any market cap.  

My first go at it was a success in that it got the phone ringing, but my response rate the second time around has been much higher since I've focused my reach to a very specific group of people. 

The info on BP covers a lot of general and specific topics and is very helpful.

The fact that you asked the question about being locked out of ones account is disturbing since if would seem you would not ask such a specific question without some source telling you this happened?  

There are specific way to structure it and minimize risk, that's why I'd like to find a local attorney who does these deals on a regular basis.  

You should also check out some local real estate investor groups such as Black Diamond REI in MA and the RI Real Estate Investor Group in RI.If you have some specific questions feel free to post them, you'll probably get several answers in short order :)

Is there a specific type of payment method to be used?

They don't need to be state specific so they work anywhere.

I would not want the current seller to fix things for me to his specification but rather to mine.

I know this will be very market specific but I have a house in a Cleveland suburb listed at 55K.